“Effective prosecutorial accountability empowers the public and makes prosecutors responsible to citizens for their actions,” he said.

“This is particularly important in a country like South Africa where officials have considerable public authority to decide who to arrest, prosecute, convict or imprison, or to award contracts worth millions to some but not others.”

He said some aspects of the NPA’s activities were scrutinised by bodies including Parliament, the auditor general, and the National Treasury, but none focused exclusively on the NPA and their staff could lack a detailed understanding of how the NPA worked.

Other countries had mechanisms, such as prosecution service inspectorates, independent complaints offices, and prosecutorial review commissions.

Newham said the NPA’s existing internal accountability mechanisms, such as the integrity management unit, did little to reassure public confidence in its institutional health and performance.

He said a debate was needed on the benefits of accountability and oversight mechanisms for the NPA, and policy-makers and criminal justice reformers should be able to draw from international good practice and experience.

President Jacob Zuma announced his decision to institute an inquiry into NPA boss Mxolisi Nxasana’s fitness to hold office, last month, after reports emerged that Nxasana had apparently not been given a security clearance because of past brushes with the law.

This included being tried for murder about 30 years ago. He was acquitted of the charge based on his version of self-defence.